package P1900;

import java.util.Scanner;

/**
 * @author: zhouyang
 * @descrpition:
 * @time: 2019-10-09 18:25
 */
public class P1914_小书童密码 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        String input = scanner.nextLine();//吸收空格
        input = scanner.nextLine();
        scanner.close();
        char[] chars = input.toCharArray();
        for(int i=0;i<chars.length;++i){
            chars[i] = (char)((chars[i]-'a'+n)%26+'a');
        }
        System.out.println(new String(chars));
    }
}
